Indented Writing
Definition
Latent impressions produced in paper sheets beneath the writing sheet by the pressure of the pen tip; invisible under normal illumination but recoverable by oblique light or ESDA.
- Cause
- Pen tip pressure on sheets under the written page
- Visibility
- Invisible under normal illumination
- Recovery methods
- Oblique light, ESDA
- Evidentiary use
- Recovers content of a removed or missing top sheet
Common questions
What can indented writing reveal that the visible document itself cannot?+
It can recover the text of a page that was written on and then torn away or never submitted, such as a note, list, or draft, giving investigators content the suspect believed had been destroyed or was never disclosed.
Why is ESDA generally preferred over oblique lighting for weak indentations?+
ESDA charges the paper surface and develops it with toner that clings preferentially to the indented grooves, which recovers far fainter and more complex impressions than oblique light can resolve by eye, particularly on textured or heavily handled paper.
Related terms
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- ESDA (Electrostatic Detection Apparatus)
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- ESDA Lift
- The permanent transparent Mylar sheet carrying the toner-developed image of the indented writing, produced by ESDA processing; suitable for court exhibition and...
- Foster+Freeman ESDA 2
- The current-generation commercial ESDA instrument (Foster+Freeman Ltd, Worcestershire, UK), used by the FBI Laboratory, DSTL (UK), Australian Federal Police, CFSL (India), and...
- Mylar Film
- A thin (approximately 6 micrometre) polyester film stretched over the document under vacuum in the ESDA process; it conforms to the document...
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